PROJECT SUMMARY (ABSTRACT) The Rakai Health Sciences Program (RHSP), Uganda, proposes an implementation science community- randomized controlled trial (CRCT) of a novel intervention to newly in-migrated individuals (?Welcome In- coming Neighbor? [WIN]), to optimize their rapid linkage to combination HIV prevention (CHP) services. RHSP data show that within the first 36 months after in-migration, compared to residents, HIV-negative in-migrants are at increased risk of HIV acquisition and HIV+ in-migrants underutilize antiretroviral therapy (ART) increasing the risk of onward transmission. The theory-based WIN intervention includes community sensitization, community-based WIN scouts (WINs), and enhanced, differentiated clinic services for in- migrants. WINs will conduct active community surveillance to rapidly identify and welcome in-migrants, provide them with information about the availability of CHP and high rates of use by residents (to ?normalize? uptake), utilize a motivational interviewing approach to encourage CHP adoption, refer in-migrants to free services, provide vouchers enabling them to receive priority clinic services, and follow-up in-migrants to assess and further encourage engagement in CHP. Specific Aims: Aim 1: To randomize 40 individually matched communities in a 1:1 ratio to the WIN intervention or control arm. In-migrants aged 15-49 in each arm will undergo a baseline and 2 follow-up surveys at ~18-month intervals. Primary end points are HIV incidence in initially HIV-negative in-migrants (n ~3,800 py per arm), and viral load suppression in HIV+ (n ~740 per arm). CHP coverage rates and sexual behaviors will also be compared (secondary outcomes). Aim 2a: To use a mixed methods approach (in-depth interviews, process & survey data) and RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) to (i) guide interim intervention adaptation as necessary; (ii) interpret trial results; and, (iii) translate the research into future action. Aim 2b: To conduct cost studies to provide information on affordability and sustainability. Innovation and Impact: This novel intervention will rapidly engage a vulnerable priority population of in-migrants, to optimize CHP and HIV impact in rural Uganda.